Hydrophylic substrate and method of manufacturing the same

ABSTRACT

According to the invention, a durable hydrophilic adsorbed film is formed on the surface of a substrate including metals, glass, plastics and the like in which the substrate has a surface layer containing hydroxyl groups or imino groups. The film is formed by covalently bonding chemical absorbents of silane groups containing a pluralilty of chloro groups to the substrate surfaces. The substrate 1 such as glass or nylon is dipped and held in a non-aqueous solution containing fluorocarbon groups and hydrocarbon groups containing chemical absorbents of silane groups containing a plurality of chloro goups including SiCl 4 , Cl 3  SiOSiCl 3 , HSiCl 3  or Cl 3  SiOSiCl 2  OSiCl 3 . After taking out the substrate 1 from the solution, drying it in a low moisture or substantially moistureless atmosphere to remove said non-aqueous solvents, the substrate is exposed to the air. A hydrophilic adsorbed ultra-thin film is thus formed by a dehydrochlorination reaction.

This application is a division of Ser. No. 08/426,477, filed Apr. 20,1995, now U.S. Pat. No. 5,629,088, which is a continuation of Ser. No.07/914,535, filed Jul. 17, 1992, now abandoned.

FIELD OF THE PRESENT INVENTION

The present invention relates to a method of making a surface of asubstrate hydrophilic. More particularly, the invention relates to amethod of making the surface of metals, ceramics, glass, plastics,synthetic fibers, paper and like materials hydrophilic by manufacturinga hydrophilic thin film.

The invention also relates to a hydrophilic fiber. More particularliy,the invention relates to high-performance chemical or synthetic fiberapparel products, such as underwear and sportswear.

BACKGROUND OF THE INVENTION

Heretofore, as a method to make the surface of metals, ceramics, glass,plastics, synthetic fibers, paper and like materials hydrophilic,silicon surface active agents, polyethylene glycol surface activeagents, poly(hydroxylethyl methacrylate) surface active agents,polyvinyl alcohol coatings, various anti-static additives includinganionic surface active agents, cationic surface active agents, non-ionicsurface active agents and ampholytic surface active agents were appliedto the surface.

Polyester, nylon, polyolefin, acrylic like synthetic fibers and rayonfibers like artificial fibers can be used in various industries for usein clothing, commercial and retail use, construction and resinreinforcement. Especially, synthetic fibers can be used due tolightness, strength, relatively low-price and variety of coloring. Inthese industries, refining the surface of synthetic fibers is oftenrequired. Applying a hydrophilic adsorbed film is one of the methods forrefining the surface.

For example, a feature of clothing such as underwear, sportswear andsocks made of polyester, nylon, acrylic and like synthetic fibers isthat it does not absorb water or moisture, which makes it possible tomanufacture light weight clothing. However, since most synthetic fibersexcept vinylon are hydrophobic, they have some problems such as beinguncomfortable when wearing due to low sweat absorbency and lowpermeability. In order to solve the problems, many attempts have beenmade. One method is to deform the fiber section. Another way is to coata surface active agent on the surface. Another way is to manufacture thefabric structure, nit fabrication, and sewing design in various ways.

Also, a further problem is that such fibers are easily electricallycharged and tend to stick to the body due to water-repellency. In orderto alleviate the problem, some methods have been taken, which add fibertreatment agents or spray anti-charging agents on the fibers.

Also, a highly hydrophilic property is useful for industrial use. Forexample, if a fishing net is highly hydrophilic, it sinks into the waterquickly. In another example, if the surface of synthetic fibers ishighly hydrophilic when strengthening the resin, adhesion between thefiber and resin will be improved. A highly hydrophilic property is alsorequired when strengthening the adhesion to the surface of cement,concrete and like materials. It is also required to make the surface ofsynthetic fibers of towels, sanitary products, diaper, sanitary napkinand like products hydrophilic.

However, the conventional methods aforementioned have a serious problemin which surface active agent molecules and coating material moleculesdo not bond covalently to the surface of a substrate, which causes poordurability. Especially, since improvement in sweat absorbency andpermeability is limited in clothings, further development is needed.

SUMMARY OF THE INVENTION

It is a primary object of this invention to provide a method to solvethe problem noted above, in which the surface of metals, ceramics,glass, plastic, synthetic fibers, paper and like materials is madehydrophilic by coating a highly-durable ultra-thin film which ismanufactured by covalently bonding the fiber surface to the hydrophilicgroup.

It is the another object of this invention to provide a method whichmakes only the fiver surface hydrophilic without adversely affecting theintrinsic features of the synthetic fibers.

According to a first aspect of the invention we provide a hydrophilicsubstrate comprising a chemically adsorbed film as a surface layercovalently bonded to the substrate by --Si-- bonds, said chemicallyadsorbed film containing polysiloxane groups.

It is preferable in this invention that the polysiloxane-containingchemically adsorbed film is laminated to a siloxane-based inner layer,the inner layer being bonded by covalent bonds to the substrate surface,the inner layer and the chemically adsorbed film being bonded togetherby covalent bonds.

It is preferable in this invention that the substrate is made of amaterial selected from the group consisting of fibers, metals, ceramics,glass, plastics, papers.

It is preferable in this invention that the substrate is a syntheticfiber, said synthetic fiber is used in the manufacture of apparelmaterial.

According to a second aspect of the invention we provide a method ofmanufacturing a hydrophilic substrate comprising the steps of contactingthe substrate containing active hydrogen groups at the surface in anon-aqueous organic solution of a silane-based surface active materialhaving a plurality of halogen groups, thereby adsorbing the silane-basedsurface active material to the substrate surface, drying in asubstantially moistureless or a low moisture atmosphere to removenon-aqueous solvent, and then reacting in a humid atmosphere to obtain achemically adsorbed polymer film at the substrate surface.

It is preferable in this invention that the material containing thesilane-based surface active material is at least one member selectedfrom the group consisting of SiCl₄, SiHCl₃, SiH₂ Cl₂, Cl(SiCl₂ O)_(n)SiCl₃ where n represents an integer from 1 to 20.

It is preferable in this invention that the non-aqueous solvent isselected from the group consisting of a hydrocarbon-based organicsolvent and a fluorocarbon-based organic solvent.

It is preferable in this invention that the active hydrogen group at thematerial surface is at least one functional group selected from thegroup consisting of a hydroxyl group, carboxyl group, an imino group andan amino group.

It is preferable in this invention that the active hydrogen groups atthe material surface are provided by a plasma or corona treatment.

Furher, according to the invention a hydrophilic monomolecular filmhaving a thickness on the order of nanometer is formed on an apparelmaterial. It is possible to selectively make only the surface of thefiber material hydrophilic. Intrinsic water-free characters of thesynthetic fiber material such as luster and resiliency are not spoiled.It is thus possible to provide a high performance apparel material,which is highly hydrophilic and has excellent feel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 (a)-(c) show a glass substrate as in example 1 of the invention.

FIGS. 2 (a)-(c) show a nylon-ABS substrate as in example 2 of theinvention.

FIGS. 3 (a)-(c) show a polyester fiber as in example 3 of the invention.

FIGS. 4 (a)-(c) show a polyurethane fiber as in example 4 of theinvention.

FIGS. 5 (a)-(c) show socks woven of a rayon fiber as in example 1 of theinvention.

FIGS. 6 (a)-(c) show socks woven of a nylon fiber as in example 2 of theinvention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is described in detail with reference to specificexamples.

A substrate having a surface which contains hydrophilic groups such ashydroxyl, carboxyl, amino and imino groups is dipped in a non-aqueoussolution containing chemical absorbents of silane groups containing aplurality of chloro groups, where a monomolecular film containingchemical absorbents of silane groups containing a plurality of chlorogroups is formed via covalent bonds as a result of a dehydrochlorinationreaction. After taking out the substrate from the solution noted above,and drying it in a substantially moistureless or a low moistureatmosphere to remove non-aqueous solvent, a laminated film containingchemical absorbents of silane groups containing a plurality of chlorogroups as noted above is formed on the surface of the monomolecularfilm. Whereafter the substrate is exposed to air and the laminated filmis polymerized due to a dehydrochlorination reaction caused by moisturein the air. At the same time, since the laminated film forms a covalentbond with said monomolecular film, and unreacted chloro groups areconverted to OH groups, an excellent hydrophilic thin film containingnumerous --OH groups can be formed on the surface of the substrate viasaid monomolecular film.

Further, usual nylon (polyamide) and polyeurethane fibers contain iminogroups (>NH) at the surface due the amide and urethane bonds. Sincepolyester and acrylic fibers contain no imino groups, the surface may beslightly oxidized by introducing hydroxyl groups. After washing thepolyamide noted above and like materials which have added hydroxyl orimino or carboxyl groups on the surface of the fiber or cloth, thefibers are dipped in a non-aqueous solution containing a plurality ofchloro groups. Thus a monomolecular film containing a plurality ofchloro groups on the fiber surface can be formed by covalent bonds aftera dehydrochlorination reaction. After taking the fiber out of thesolution and drying in a substantially moistureless or low moistureatmosphere, the laminated film containing the plurality of chloro groupscan be formed on the surface of the monomolecular film. Thereafter, thislaminated film is polymerized by a dehydrochlorination reaction afterexposing to air containing moisture (i.e., humid air). At this time, thelaminated film forms covalent bonds with the monomolecular film.Furthermore, the ultra-thin hydrophilic polysiloxane film containing alarge amount of OH groups which are bonded to the fiber surface can beformed.

As a non-aqueous solvent, hydrocarbon or fluoroalkyl groups are suitablebecause of their non-toxicity. This invention relates to syntheticfibers such as polyester, nylon, polyolefine, acrylic fiber, aramidofiber and chemical fiber such as rayon, and natural fibers such ascotton, hemp, silk and wool.

This invention is useful for making the following materials hydrophilic:clothing, bath and sanitary products, sanitary napkins, sheets, interioritems such as carpets, fishing nets, fishing line, tire cord forindustrial use, materials for use in construction, and materials usedfor reinforcing resin.

The apparel, to which the invention pertains, includes underwear,sportswear and other materials. The following description of examplesconcerns textiles made of polyester, acrylic, nylon, polyurethanefibers.

Fiber materials such as socks woven of said fiber having a surfacecontains hydrophilic groups such as hydroxyl, carboxyl, amino and iminogroups are dipped in a non-aqueous solution containing chemicalabsorbents of silane groups containing a plurality of chloro groups,where a monomolecular film containing chemical absorbents of silanegroups containing a plurality of chloro groups is formed via covalentbonds formed by a dehydrochlorination reaction. After taking out thefiber material or socks from the solution noted above, and drying it ina substantially moistureless or low moisture atmosphere to removenon-aqueous solvent, a laminated film containing chemical absorbents ofsilane groups containing a plurality of chloro groups as noted above isformed on the surface of the monomolecular film. Whereafter thesubstrate is exposed to air and the laminated film is polymerized due toa dehydrochlorination reaction due to moisture in the air. At the sametime, since the laminated film forms a covalent bond with saidmonomolecular film, and unreacted chloro groups are converted to OHgroups, an excellently hydrophilic ultra-thin film containing numerous--OH groups can be formed on the surface of the substrate via saidmonomolecular film.

Examples of this invention include stockings for women, socks for menand women, sports socks, tights and Japanese socks (tabi).

As chemical absorbents of silane groups containing a plurality of chlorogroups SiCl₄, SiHCl₃, SiH₂ Cl₂, Cl(SiCl₂ O)_(n) SiCl₃ (where nrepresents an integer from 1 to 20), are suitable due to having manyactive sites for a dehydrochlorination reaction.

As a non-aqueous solution, hydrocarbon or fluoroalkyl groups aresuitable because of their non-toxicity. According to the invention, themethod of making subtrates hydrophilic can be attained by using SiCl₄,SiHCl₃, SiH₂ Cl₂, Cl(SiCl₂ O)_(n) SiCl₃ (where n represents an integerfrom 1 to 20), as chemical absorbents containing a plurality of chlorogroups and using hydrocarbon or fluoroalkyl groups as a non-aqueoussolution. The following examples concern the typical methods of makingsubstrates hydrophilic.

EXAMPLE 1

A processed glass substrate 1 (according to whichever materials arepreferred such as metals, ceramics, plastic, synthetic fibers and likematerials of which surfaces contain functional groups includinghydroxyl, carboxyl and imino groups which cause a dehydrochlorinationreaction with a chlorosilane group) was prepared (FIG. 1 (a)). Afterwashing, the glass substrate was dipped and held in a fluoroalkyl groupsolution (e.g., AFLUID manufactured by ASAHI GLASS Co.) for ten minutescontaining chemical absorbents of silane groups containing a pluralityof chloro groups, e.g., a solution containing 1% by weight of SiCl₄ (or,SiHCl₃, SiH₂ Cl₂, Cl(SiCl₂ O)_(n) SiCl₃ where n represents an integerfrom 1 to 20, was available). The surface of the substrate containshydroxyl groups 2, and the chemical bonds are attained as follows(Formula 1!). ##STR1##

Thus, siloxane-containing monomolecular film 3 containing numerous Clgroups were formed. The film was covalently bonded to the surface of thesubstrate. The covalent bonds were via siloxane bonds (FIG. 1 (b)).

Without washing with an organic solvent, the glass substrate wassubsequently dried in a substantially moistureless or low moistureatmosphere, preferably less than or equal to about 5% relative humidity.Thus, SiCl₄ molecules remaining on the glass substrate surface formed alaminated film 4 having a thickness of about 10 nm. Thereafter, thelaminated film was polymarized by a dehydrochlorination reaction withmoisture (i.e., humid air at greater than or equal to about 30% relativehumidity) contained in the atmosphere. As a result, since the laminatedfilm formed a covalent bond with the monomolecular film 3 and unreactedchloro groups were converted to OH groups, the ultra-thin hydrophilicfilm 5 was formed as represented by formula 2!. ##STR2##

As a result, the ultra-thin hydrophilic polysiloxane film 5 containing alarge amount of --OH groups was formed on the surface of the glasssubstrate (FIG. 1 (c)).

The formation of the covalently adsorbed monomolecular film wasconfirmed by FTIR spectrometry, and its thickness was measured about 0.3nm by ESCA.

This ultra-thin film was perfectly bonded by covalent bonds to the glasssubstrate and did not separate at all during rubbing or washing thefilm. Moreover, the ultra-thin film is so highly hydrophilic that awater-wetting angle could not be measured.

EXAMPLE 2

Processed nylon resin (polymer alloy or polymer blend) substrate 11 wasprepared (FIG. 2 (a)). After washing, the substrate was dipped and heldfor 10 minutes in a fluoroalkyl solution such as normal hexanecontaining chemical absorbents of silane groups containing a pluralitychloro groups, e.g., a solution containing 1% by weight of Cl₃ SiOSiCl₃(SiHCl₃, Cl₃ SiOSiCl₂ OSiCl₃ was available). The surface of substrtatecontained imino groups (>NH) 12, and covalent bonds were formed asfollows (Formula 3!). Thus a siloxane-containing monomolecular film 13containing numerous Cl groups was formed. The film was covalently bondedto the surface of the substrate. The covalent bond was via siloxanebonds (FIG. 2 (b)). ##STR3##

Without washing with an organic solvent, the substrate was subsequentlydried in a low atmosphere, preferably less than or equal to about 10%relative humidity. Thus, Cl₃ SiOSiCl₃ molecules remaining on thesubstrate surface formed the laminated film 14 which had a thickness ofabout 20 nm. Thereafter, the laminated film was polymerized due by adehydrochlorination reaction with moisture (greater than or equal toabout 30% relative humidity) contained in the atmosphere. As a result,since the laminated film formed a covalent bond with the monomolecularfilm as shown in formula 3! and unreacted chloro groups were convertedto OH groups, the ultra-thin hydrophilic film 15 containing numerous--OH groups bonded to the surface of the substrate (FIG. 2 (c)).

The formation of the covalently adsorbed monomolecular film wasconfirmed by FTIR spectrometry, and its thickness was measured about 0.3nm by ESCA.

This ultra-thin film was perfectly bonded by covalent bonds to thesubstrate and did not separate at all by rubbing or washing the film.Moreover, the ultra-thin film is so highly hydrophilic that awater-wetting angle could not be measured.

We mentioned a glass or nylon-ABS (polymer alloy or polymer blend) resinas a substrate in the example noted above. However, other substrates areavailable which contain functional surface groups such as hydroxylgroups, imino groups, and carboxyl groups that cause adehydrochlorination reaction with chlorosilane groups.

EXAMPLE 3

A processed polyester sports shirt or cloth (alternatively acryliccloth) was prepared. To introduce hydroxyl groups which react withchlorosilane on the surface of the cloth, the cloth was dipped in asolution containing dichromate at 70° C. for thirty minutes. The surfaceof the cloth was thus oxidized (FIG. 3 (a)). Thereafter, the cloth wasdipped and held in a fluoroalkyl group solution (e.g., AFLUIDmanufactured by ASAHI GLASS) for ten minutes containing chemicalabsorbents of silane groups containing a plurality of chloro groups,e.g., a solution containing 1% by weight of SiCl₄, (HSiCl₃, SiH₂ Cl₂,Cl₃ SiOSiCl₃, Cl₃ SiOSiCl₂ OSiCl₃ was available).

The surface of the cloth contains hydroxyl groups 22 and the chemicalbonds are formed as follows (Formula 4!). ##STR4##

Thus, a siloxane-containing monomolecular film 23 containing numerous Clgroups were formed. The film was covalently bonded to the surface of thecloth. The covalent bonds were via siloxane bonds (FIG. 3 (b)).

Without washing with an organic solvent, the cloth was subsequentlydried in a low moisture atmosphere, preferably less than or equal toabout 5% relative humidity. Thus, SiCl₄ molecules remaining on the clothsurface formed the laminated film 24 which had a thickness of about 10nm. Thereafter, the laminated films were polymerized due to adehydrochlorination reaction with moisture (greater than or equal toabout 30% relative humidity) contained in the atmosphere. As a result,since the laminated film forms a covalent bond with monomolecular film 3noted above, and unreacted chloro groups were converted to OH groups,the ultra-thin hydrophilic film 25 containing numerous OH groups bondedto the surface of the substrate cloth (FIG. 4 (b)).

The formation of the covalently adsorbed monomolecular film wasconfirmed by FTIR spectrometry, and its thickness was measured about 0.3nm by ESCA.

This ultra-thin film was perfectly bonded by covalent bonds to the clothand did not separate at all in by rubbing or washing the film. Moreover,the ultra-thin film was so highly hydrophilic that a water-wetting anglecould not be measured.

EXAMPLE 4

Processed nylon underwear (alternatively polyurethane cloth) 31 wasprepared (FIG. 4 (a)). After washing, the cloth was dipped and held for10 minutes in a fluoroalkyl solution such as normalhexane containingchemical absorbents of silane groups containing a plurality of chlorogroups, e.g., a solution containing 1% by weight of Cl₃ SiOSiCl₃(SiHCl₃, Cl₃ SiOSiCl₂ OSiCl₃ was available). The surface of the clothcontains imino groups 32 and the chemical bonds are attained as follows(Formula 5!). Thus, a siloxane-containing monomolecular film 33containing numerous Cl groups were formed. The film was covalentlybonded to the surface of the cloth. The covelent bond was via siloxanebonds (FIG. 4 (b)). ##STR5##

Without washing with an organic solvent, the substrate was subsequentlydried in a low moisture atmosphere, preferably less than or equal toabout 10% relative humidity.

Thus, Cl₃ SiOSiCl₃ molecules remaining on the substrate surface formedof the laminated film 34 which had a thickness of about 20 nm.Thereafter, the laminated films were polymerized due to adehydrochlorination reaction with moisture (greater than or equal toabout 30% relative humidity) contained in the atmosphere. As a result,since the laminated film forms a covalent bond with the monomolecularfilm as shown in (formula 5!) and unreacted chloro groups were convertedto OH groups, the ultra-thin hydrophilic film 35 containing numerous OHgroups bonded to the surface of the substrate (FIG. 4 (c)).

The formation of the covalently adsorbed monomolecular film wasconfirmed by FTIR spectrometry, and its thickness was measured about 0.3nm by ESCA.

This ultra-thin film was perfectly bonded by covalent bonds to thesubstrate and did not separate at all by rubbing or washing the film.Moreover, the ultra-thin film was so highly hydrophilic that awater-wetting angle could not be measured.

We mentioned a fiber or a cloth as examples noted above, however,artificial leather or synthetic resins and the like can be used.

EXAMPLE 5

Socks woven of mixed-spun thread (polyester fiber 70 wt % rayon fiber 30wt %) 41 was prepared. However, polyurethane fiber was used in theinside upper part of the socks to keep them from slipping down (FIG. 5(a)). It is possible that other fibers which contain functional surfacegroups that cause dehydrochlorination reaction with chlorosilane groupcould be used instead of the fibers noted above. After washing, thesocks were dipped and held in a fluoroalkyl group solution (e.g. AFLUIDmanufactured by ASAHI GLASS Co.) for ten minutes containing chemicalabsorbents of silane groups containing a plurality of chloro groups,e.g., a solution containing 1% by weight of SiCl₄ (or, SiHCl₃, SiH₂ Cl₂,Cl(SiCl₂ O)_(n) SiCl₃ where n represents an integer from 1 to 20, wasavailable). The surface of rayon fiber contains hydroxyl groups 42 andchemical bonds were attained as follows (Formula 6!). ##STR6##

Thus, a siloxane-containing monomolecular film 43 containing numerous Clgroups were formed. The film was covalently bonded to the surface of thesocks. The covalent bonds were via siloxane bonds (FIG. 5 (b)).

Without washing with an organic solvent, the socks were subsequentlydried in a low moisture atmosphere, preferably less than or equal toabout 5% relative humidity. Thus, SiCl₄ molecules remaining on the clothsurface formed the laminated film 44 which had a thickness of about 10nm. Thereafter, the laminated films were polymerized due to adehydrochlorination reaction with moisture (greater than or equal toabout 30% relative humidity) contained in the atmosphere. As a result,since the laminated film forms a covalent bonds with the monomolecularfilm 43, and unreacted chloro groups were converted to OH groups, theultra-thin hydrophilic film 45 containing numerous OH groups bonded tothe surface of the substrate cloth (FIG. 5 (c)).

The formation of the covalently adsorbed monomolecular film wasconfirmed by FTIR spectrometry, and its thickness was measured about 0.3nm by ESCA.

This ultra-thin film was perfectly bonded by covalent bonds to the clothand did not separate at all by rubbing or washing the film. Moreover,the ultra-thin film was so highly hydrophilic that a water-wetting anglecould not be measured.

EXAMPLE 6

Processed nylon stockings 51 were prepared (FIG. 6 (a)). After washing,the stockings were dipped and held for 10 minutes in a fluoroalkylsolution such as normalhexane containing chemical absorbents of silanegroups containing a plurality chloro groups, e.g., a solution containing1% by weight of Cl₃ SiOSiCl₃ (SiHCl₃, Cl₃ SiOSiCl₂ OSiCl₃ wasavailable). The surface of the substrate contained imino groups 52 andchemical bonds were attained as follows (Formula 7!). ##STR7##

Thus, a siloxane-containing monomolecular film 53 containing numerous Clgroups were formed. The film was covalently bonded to the surface of thesubstrate. The covelent bonds were via siloxane bonds (FIG. 8 (b)).

The formation of the covalently adsorbed monomolecular film wasconfirmed by FTIR spectrometry, and its thickness was measured about 0.3nm by ESCA.

Without washing with an organic solvent, the substrate was subsequentlydried in a low moisture atmosphere, preferably less than or equal toabout 10% relative humidity.

Thus, Cl₃ SiOSiCl₃, molecules remaining on the substrate surface formedthe laminated film 54 which had a thickness of about 20 nm. Thereafter,the laminated films were polymerized due to a dehydrochlorinationreaction with moisture (greater than or equal to about 30% relativehumidity) contained in the atmosphere. As a result, since the laminatedfilm formed a covalent bonds with the monomolecular film as shown in(formula 7!) and unreacted chloro groups were converted to OH groups,the ultra-thin hydrophilic film 55 containing numerous OH groups bondedto the surface of the substrate (FIG. 4 (c)).

This ultra-thin film was perfectly bonded by covalent bonds to thesubstrate and did not separate at all by rubbing or washing the film.Moreover, the ultra-thin film was so highly hydrophilic that awater-wetting angle could not be measured.

We have already mentioned mixed-spun fiber cloth of polyester and rayon,or nylon in the above examples of socks and stockings which are wovenwith such fibers. However, it is possible that other fibers whichcontain functional surface groups that cause a dehydrochlororinationreaction with chlorosilane groups could be used instead of the fibersnoted above. As a non-aqueous solvent, whichever solvent is preferable,provided that it does not dissolve the fiber, does not contain moistureand does not react with the chlorosilyl groups may be used.

As shown in the examples of this invention, socks 51 woven of fiberwhich has a surface containing imino groups 52 and like groups wasdipped and held in a non-aqueous solution containing chemical absorbentsof silane groups containing chloro groups. Thus, a monomolecular film 53containing chemical absorbents of silane groups containing a pluralityof chloro groups was formed on the fiber surface by covalent bonds by adehydrochlorination reaction. This film was polymerized 54 in adehydrochlorination reaction with moisture by exposing to the air. Thus,the laminated film was covalently bonded to the monomolecular film, andthen unreacted chlorosilane groups were converted to --OH groups. Thusthe ultra-thin hydrophilic polysiloxane film 55 containing numerous OHgroups bonded to the surface of the fiber. As a result, by covering thesurface of synthetic fiber socks with an ultra-thin film containingpolysiloxane, and by covalently bonding the ultra-thin film with thesurface of the fiber, the socks comfortable when worn, and durable. Thedesirable effects such as excellent water-absorbency were realized.

As has been shown, this invention is greatly beneficial for forming anultra-thin film containing numerous hydrophilic functional groups on thesurface of synthetic fiber. Accordingly, if sweat wets the fiber, andthen spreads over the whole surface, the film does not separate at alldue to the firm covalent bonding with the surface of the fiber.Moreover, since the thickness of the ultra-thin film is on the level ofdozens of namometers, deterioration of the intrinsic the flexibility offiber does not occur. Therefore, the film improves wettability of thesynthetic fiber.

As has been shown, according to this invention, an excellent hydrophilicultra-thin film is formed on the surface of a substrate by covalentbonds via a chemically adsorbed monomolecular film. Therefore, thisinvention provides a simple method for obtaining a durable hydrophilicfiber.

As has been shown, with the method of manufacture according to theinvention, since an ultra-thin film containing hydrophilic functionalgroups is bonded to surface of the fiber via chemically adsorbedmolecules, a hydrophilic can be manufactured efficiently.

As has been shown, the invention is greatly beneficial to industry.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiment is to be considered in all respects as illustrative and notrestrictive, the scope of the invention being indicated by the appendedclaims rather than by the foregoing description and all changes whichcome within the meaning and range of equivalency of the claims areintended to be embraced therein.

We claim:
 1. A method of manufacturing a hydrophilic substratecomprising:(a) contacting a surface of a substrate having activehydrogen groups on said surface with a non-aqueous organic solution of asilane-based surface active material having a plurality of halogengroups, thereby adsorbing said silane-based surface active material tosaid surface of said substrate, (b) drying said surface of saidsubstrate having silane-based surface active material adsorbed theretoin a substantially moistureless atmosphere to remove non-aqueoussolvent, and (c) then reacting said surface of said substrate havingsilane-based surface active material adsorbed thereto in atmospherecontaining water vapor to obtain a chemically adsorbed polymer film onsaid surface of said substrate.
 2. The method of manufacturing ahydrophilic substrate according to claim 1, wherein said silane-basedsurface active material is at least one compound selected from the groupconsisting of SiCl₄, SiHCl₃, SiH₂ Cl₂ and Cl(SiCl₂ O)_(n) SiCl₃, where nrepresents an integer from 1 to
 20. 3. The method of manufacturing ahydrophilic substrate according to claim 1, wherein said non-aqueoussolvent is selected from the group consisting of a hydrocarbon-basedorganic solvent, and a fluorocarbon-based organic solvent.
 4. The methodof manufacturing a hydrophilic substrate according to claim 1, whereinthe active hydrogen group on said surface of said substrate is at leastone functional group selected from the group consisting of a hydroxylgroup, a carboxyl group, an imino group and an amino group.
 5. Themethod of manufacturing a hydrophilic substrate according to claim 1,further comprising forming said active hydrogen groups on said surfaceof said substrate by a plasma or corona treatment.